Judith Krug, 69, a stalwart defender of freedom of information, unrestricted Internet access at public libraries and the founder of the American Library Association's Banned Books Week, died April 11 at a hospital in Evanston, Ill. She had stomach cancer.

Director of the ALA's Office for Intellectual Freedom since 1967, Mrs. Krug was a national leader in several legal cases that rose to the Supreme Court. She organized the successful legal campaign to overturn the 1996 Communications Decency Act, which was Congress's first attempt to censor online speech. She publicly objected to the Department of Justice's searches of previously confidential library records, which were conducted under the Patriot Act of 2001.

She also led the partially successful 2003 effort to overturn the Children's Internet Protection Act; the Supreme Court ruled that the act was constitutional but that filters on library computers could be turned off at an adult's request.

"From our perspective, she was central to many of the battles that gave modern interpretation to the First Amendment," said Leslie Harris, president and chief executive of the Center for Democracy and Technology, a nonprofit organization on whose board Mrs. Krug served.

"Her fingerprints are literally on every case having to do with library freedom [and] the rights of minors to access information. . . . She was the kind of person who comes along once in a generation."

Library organizations were effusive in their praise of her. ALA President Jim Rettig called her "always principled and unwavering," and the Library Journal, in a 2005 editorial, said, "Her service to intellectual freedom . . . has been tremendous."

She also advised countless librarians on dealing with challenges to books and other materials on their shelves, defending everything from Mark Twain's "The Adventures of Huckleberry Finn" to standard American dictionaries.

In 1982, Mrs. Krug established the ALA's annual Banned Books Week, the last week of September, to celebrate freedom of choice and expression.

Librarians, under pressure from community demands to limit book and Internet access to minors, did not always agree with Mrs. Krug's absolutist positions. But she argued that the government should not interfere in Americans' right to obtain and examine information. Parental decisions on what children should read or view should be enforced by parents, not the government, she argued.

"We're the only country in the world where everybody has access to the library and everything in it," she told The Washington Post in 1994. "If you don't like something, okay, tell your kids you don't want them to read it. That works. It really works. Every once in a while, the kids are going to defy you. But so what?"

The same philosophy applied to Internet filtering technology, used to block online pornography. But the filters, she noted in 2002, are imperfect and often inadvertently block important information on health, sexuality and social issues.

"Instead of relying on filtering technology, we should be educating children," she said. "It's not only learning the difference between right and wrong, but how to use information wisely. . . . There are no quick fixes."

She was one of the few people to publicly challenge the Patriot Act shortly after its passage. Her stance brought her hate mail, which frustrated her. Unafraid to challenge the nation's highest officials on matters of principle, she "considered it a badge of honor that former Attorney General John Ashcroft dismissed the protests of civil libertarians against the excesses of the Patriot Act as having been organized by 'a bunch of hysterical librarians,' " said Judith Platt, president of the Freedom to Read Foundation.

A native of Pittsburgh, Judith Fingeret graduated from the University of Pittsburgh and received a master's degree in library science from the University of Chicago in the early 1960s. She worked for several Chicago libraries before joining the ALA in 1967.

She helped found the Freedom to Read Foundation, which works closely with the ALA, and has served as its executive director since 1969.

In 1998, the ALA gave her the profession's highest honor, the Joseph P. Lippincott Award. She also received the William J. Brennan Jr. Award from the Thomas Jefferson Center for the Protection of Free Expression earlier this year for her "remarkable commitment to the marriage of open books and open minds."

Survivors include her husband of 45 years, Herbert Krug of Evanston; two children, Steven M. Krug of Northbrook, Ill., and Michelle Litchman of Glencoe, Ill.; two brothers; and five grandchildren.